DVW-A500 firmware upgrade

One of our a500's is not on the last firmware issued, which add audio data options (for Dolby E use). This is not a huge issue, but the firmware is about $100 and I'd be willing to do that to get it up to date.

We've bone Dolby E on the unit before (without knowing better) and it all seems to work fine. But nevertheless. . .

I scoured some technical bulletins and I've learned that the last firmware release won't work unless we have the right EQ 45 board (which we do) and the right APR-1 board (which we don't). We need version V2.10 MPU of the APR-1 board.

According to Sony Parts this card is $1800+ in which case forget it.
The part I believe i need is A-8275-144-B

Is there a used part resource and/or a way that this board can be brought up to version V2.10 MPU?